Along with the progress of semiconductor packaging technology and improvements in electrical performance of semiconductor chips, semiconductor devices are becoming highly integrated. The traditional lead frame semiconductor device is gradually being replaced with ball grid array (BGA) and a flip chip ball grid array (FCBGA) package structures, wherein a plurality of input/output (I/O) connections are formed on these semiconductor devices for accommodating electronic circuits and semiconductor chips therein.
In accordance with the high integration of the semiconductor device, more leads and circuits are required, thus increasing the generation of noise. Generally, in order to reduce the noise or compensate the electrical properties, passive components such as resistors, capacitors, and inductors are incorporated in the semiconductor device to reduce noise and stabilize the circuitry to meet the requirements for the electrical characteristics of the packaged semiconductor chip.
Conventionally, the passive components are mounted on the circuit board in areas not occupied by semiconductor chips. However, this arrangement requires a relatively large circuit board and undesirably increases the overall size of the product incorporating the circuit board. Moreover, the passive components mounted on the circuit board also increases the complexity of the circuit layout and fabrication processes for the semiconductor device. Referring to FIG. 1, a plurality of passive components 12 are disposed on a surface of a circuit board 1, wherein the circuit board 1 can be a normal printed circuit board or a chip-carrying circuit board. Conventionally, in order to reduce the degree that the passive components 12 affect the electrical connections between the semiconductor chips 11 and a plurality of bond fingers formed on the circuit board 1, the passive components 12 are situated at corner positions of the circuit board 1 or at regions outside where the semiconductor chips 11 are mounted. However, considering the space and specific locations required for the bond pads, the number of and mounting locations for passive components 12 is undesirably restricted. Moreover, since the number of passive components 12 generally increases with enhanced performance of a semiconductor device, use of the above conventional arrangement to incorporate more semiconductor chips 11 and more passive components 12 on the circuit board 1 would not only increase the size of the semiconductor device, but also fail to comply with the requirement for a small product profile.
Furthermore, in response to the enhanced functionality and smaller sizes of electronic products, lamination technology needs to be improved for fabricating circuit boards with smaller thicknesses, multiple layers and higher densities. Therefore, for making the circuit boards more compact in size, a type of multi-layer circuit board embedded with passive components has been developed, wherein the passive components are mounted in the form of films between laminations of the multi-layer circuit board.
The multi-layer circuit boards integrated with various films of passive components can be arranged in different configurations. Referring to FIG. 2, a capacitive film 22 is embedded in a multi-layer circuit board 2, wherein it can be a dielectric layer with a high dielectric constant that is made of a polymeric material, ceramic material, polymer filled with ceramic powders and the like. Patterned conductive circuit layers 21 are formed on opposite surfaces of the capacitive film 22 and comprise several circuit regions serving as electrodes 21b of capacitors 22a, in order to form a multi-layer circuit board structure with embedded capacitors.
Materials and methods for forming passive components such as capacitors in the laminated structure of a circuit board are being highly refined. Referring to related prior arts in this field including U.S. Pat. Nos. 3,857,683, 5,243,320 and 5,683,928, it is usual to form passive components on an organic insulating layer by printing and/or photoresist-etching techniques before fabricating a new lamination for a multi-layer circuit board.
However, although embedding films of passive components between laminations of the multi-layer circuit board is capable of solving the aforementioned problem that restricts trace routability of the circuit board, it still has a drawback. Since the passive components are disposed between laminations of the circuit board, in cases where different electrical characteristics such as capacitance, resistance or inductance are required, the multi-layer circuit board needs to be re-designed and re-laminated, which significantly increases fabrication costs and causes difficulty in managing material stocks.
Therefore, the problem to be solved is to provide for a significant number of passive components in the semiconductor device or electronic device to enhance the electrical performance without affecting trace routability and increasing fabrication and material costs of the semiconductor device or electronic device in accordance with the current trend of reducing the size and improving the functionality for electronic products.